Generic valves of this type comprise a housing and an actuating mechanism for the closure element, for example a valve flap. Such valves further comprise a port for fluid intake and two ports for fluid outlet, and are used, for example, as bypass valves for directing the exhaust gas flow from motor vehicles into different fluid routes, based upon requirements.
One example of a use for said generic valves is for either conducting the flow of exhaust gas to the exhaust gas heat exchanger in gasoline and/or diesel engines for the purpose of reducing harmful emissions from diesel engines, increasing the efficiency of gasoline engines, or conducting the exhaust gas flow via a bypass for energy input into the engine coolant in diesel and gasoline engines and in hybrid vehicles.
In the prior art, valves of this type are known in practical implementation as bypass dampers, and are constructed with a cast steel or cast aluminum housing or a stamped sheet metal housing, with a fixedly mounted flap.
In valves in which the valve housing is embodied as a cast component, it is a particular disadvantage that these valves are quite heavy. Moreover, the cost of producing said valves is high, due, among other things, to the correspondingly high cost of tools and expensive individual components.
Cast housings have the further disadvantage of offering poor accessibility to the interior of the valve housing for performing work on the housing.
The stated disadvantages of cast housings have been acknowledged and even overcome in the prior art to some extent by an exhaust gas valve according to German Pat. Appl. Pub. No. DE 103 39 623 A1. German Pat. Appl. Pub. No. DE 103 39 623 A1 discloses a valve which has a sheet metal valve housing. The sheet metal valve housing is embodied as a funnel-shaped or pot-shaped deep-drawn sheet metal part having a housing opening at the narrower end and a larger housing opening at the wider end. The special feature of this design is the separate flange plates mounted at the ports and covering the housing openings, which plates have defined openings and connection options along with separately machinable sealing surfaces for the valve flaps.
Disadvantages of the prior art include, for one, the costly use of cast housings having a complex level of machining, and for another, in the case of bypass dampers having a stamped housing, and problems with internal leakage due to a lack of flexibility of the flap, which impacts the cooling capacity of the exhaust gas heat exchanger.